How to identify tube amp


I just received a pair of mono blocks that don’t have any branding or identification.  It didn’t come with tubes so I’m not sure what tubes to buy for it!  How do I identify who manufactured the amp and/or figure out what tubes to get for it?
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By weight. Different manufacturers used different transformers, so you could weigh it.

(I'm joking).

Take pictures and share them.
This begs the question if you just received them who/where did they come from? Did you purchase them? If so did the seller not identify the amps or give any details?
Also looking at the pics I see two spots for input tubes and two for output tubes which implies the amp is single ended. You can start there classic single ended tubes would be 300B, 2A3, 45. There are certainly instance of single ended amps using a variety of other tubes EL84 and EL34, KT88. Perhaps someone can better tell by the tube sockets I cannot.